Ultrasound markers in the detection of Down's syndrome

Abstract

Introduction: Down syndrome is the result of the triplication of genetic material derived from chromosome 21. Approximately 94 % of the cases originate from the absence of disjunction in the first meiosis. In recent years the technological development of high resolution ultrasonography and its use in the examination of fetal anatomy have allowed the description of multiple genetic markers of chromosomal abnormalities in the fetus, especially trisomy 21.

Objective: to present a case that illustrates the usefulness of prenatal detection of echographic markers of Down syndrome.

Case presentation: a patient aged 35 years and 20 weeks gestation whose fetus was detected in prenatal ultrasound, severe heart disease, a disease that affects 40-50 % of fetuses with trisomy 21. Therefore, ultrasonographic search of other echographic markers of Down syndrome was carried out. According to the identified ultrasonographic findings and the diagnostic criteria, the couple received multidisciplinary advice at the Provincial Center of Medical Genetics, and decided on the elective interruption of the pregnancy. The anatomopathological examination of the fetus confirmed the presence of the findings identified in the prenatal ultrasound.

Conclusions: although the cytogenetic study is considered the definitive method for the prenatal diagnosis of chromosomopathies, the high sensitivity of the ultrasound allows the detection of markers consistent with Down syndrome. This could be an alternative to avoid carrying out invasive procedures such as genetic amniocentesis or corial biopsy in pregnant women at high risk